1.2 (AQZ) Not running after timing chain replaced WHY???

**d4rr4gh** · 25-05-2011,12:21 AM

Hi there, I recently bought a 2004 Seat Ibiza (yes I know this is the Volkswagen section but its currently got a Polo engine in it - as if that matters).
Anyway, at about 75000 miles, my sister got in one day and the engine wouldn't start. So she turned it over and over and over. Then called my dad out and he tried it and it started, ran rough for a second or 2 on 1 or 2 cylinders, and then died. So i came out to tow it to my friend's house but turned it over just to see what would happen and the same thing happened - a second or 2 of running on 1 or 2 cylinders before it died.

My friend stripped it down, put a new timing kit on it, and tried to start it but it wouldn't run. Took the cylinder head off and sent it over to an engineers (Comiskey's in Portadown, NI - a reputable place) where they replaced 6 valves and did whatever else they do to refurbish a cylinder head in exchange for £300. Lovely.

Only when the reconditioned head went back on, the car still wouldn't start.

At this stage, my friend had spent a serious amount of time on it, and told me that I'd be better off just putting a new engine in it. So I bought a Polo engine for £300 from a scrap yard. He put that in and then told me that it still won't start. He says that it starts but runs on 1 or 2 cylinders for about 5 seconds before cutting out.

How is this possible? He's checked the compression on all cylinders, he's checked the timing, he's checked that its getting fuel and spark, but its not running. The only thing I can think of is that its delivering the fuel/spark at completely the wrong time. To me, that also explains why its sort of running for a few seconds when you start it - its just using what's in the cylinders.
But is the fuelling and spark not all controlled by the ECU? It just doesn't make sense to me that the engine could be timed up correctly but delivering fuel and spark at the wrong times.

Has anyone got any idea what's going on?

**d4rr4gh** · 25-05-2011,12:42 AM

Oh yeah, and the diagnostics light isn't on and its been checked on a computer with no fault codes registering.

**Flash2** · 25-05-2011,07:39 PM

Were any parts from the original engine used on the 'new' engine? Could the EGR valve be jammed open or something? There is something in the back of my mind about fuel filters on those engines. Something to do with the fuel pressure regulator which is built into the filter. I can't remember now what the problem was. I'll look through my notes at work and if I find anything relevant I'll report back.

Jim.

**d4rr4gh** · 26-05-2011,08:16 AM

Yeah, the only "new" part was the block itself. I'll check the EGR valve, and let me know about the pressure regulator. But would both of those issues not throw up a fault code?

**Crasher** · 26-05-2011,10:58 AM

Did he use the two cam locking pins and crank locking pin to set the timing? Has he scanned it for fault codes? Has he done a compression test? If it is timed, has compression, it has no codes, fuel is there and it has a spark, it should run so he is missing something. A similar thing happened to me once on one of these and it was two failed coil packs so you could do worse than to fit three new coil packs, but don’t fit cheap ones, buy them genuine.

**d4rr4gh** · 26-05-2011,01:50 PM

Originally Posted by Crasher

Did he use the two cam locking pins and crank locking pin to set the timing? Has he scanned it for fault codes? Has he done a compression test? If it is timed, has compression, it has no codes, fuel is there and it has a spark, it should run so he is missing something. A similar thing happened to me once on one of these and it was two failed coil packs so you could do worse than to fit three new coil packs, but don’t fit cheap ones, buy them genuine.

Thanks Crasher
Yes: Checked the timing with the Sealey tools
Yes. Scanned for codes and none present
Yes. Good compression on all 3 cylinders
(and this is all true for the old engine too)

OK, so now we're talking about replacing something completely unrelated to what caused the original problem. Sounds a bit unlikely to me. I just don't want to keep throwing money at this unless I have a bit more to go on. I dunno. What do you think? Is there anything else that you can think of? Any chance its an ECU problem? And I take it that the fact that its getting spark doesn't mean that the coil packs are ok?

**Crasher** · 26-05-2011,03:22 PM

Testing the coil packs like I assume he has done can easily damage them and they will still produce a spark in atmospheric conditions but not under pressure in the cylinder. It may be that the coil packs have failed due to being removed many times, it has happened to me on a number of occasions. If it has fuel, air, spark, compression, timing and no fault codes then all I can suggest is a set of coil packs.

**d4rr4gh** · 26-05-2011,04:32 PM

Cheers Crasher, I'll pass on the info and see what he says :-)

**d4rr4gh** · 26-05-2011,08:09 PM

Just talked to my friend and he says that if the problem was with the coil packs, a coil pack/misfire fault code would have come up when he scanned it for faults?
Though he's wondering if there could be an issue with the ECU needing reset or the software being old or something and maybe that's why no codes have appeared?